"It is an exceptional discovery because a barracks has never been identified before in Rome, nor a domus connected to the barracks," said Rome's archaeological superintendent, Rossella Rea.

The domus of the commander was found about 12 metres under the level of the Amba Aradam station, near the Basilica of San Giovanni Laterano (St John Lateran). The house will now be dismantled, level by level, and temporarily moved to another site before being placed back at its original site, sources said.

Heated containers will be used to keep it pristine during the move, while work will then resume at the Amba Aaradam metro stop.

Rome Archaeological Heritage Superintendent Francesco Prosperetti said he had already been in touch with national anti-corruption body ANAC chief Raffaele Cantone to help preserve the integrity of the find.

"He assured me that the place will be made accessible to the public and the whole find will be put back in its place," said Prosperetti. "Exactly how this will happen, compatibly with the metro C line, we'll have to see".

Prosperetti said he had "already secured planning and funding" for the project. ANAC and Cantone has to sign off on all major public works in Italy.

The dig has unearthed two spaces dating to the middle of the imperial period which, due to a fire, feature well-conserved parts of a wooden ceiling and furniture.

"The material is only conserved in exceptional environmental and climatic conditions, or after special events like those that took place at Herculaneum and Pompeii," said sources at Rome's special superintendency. "The discovery of a burned wooden ceiling is unique for the city".

The excavation in via dell'Amba Aradam also found the skeleton of the dog, curled up in front of a door and "likely trapped inside the building at the time of the fire," sources said.

The remains of a smaller animal, which have yet to be identified, were also uncovered. A fine black and white mosaic floor was also found.

"What makes this find resemble Pompeii is that we have evidence of a moment in history," said Prosperetti at the time. "The fire that stopped life in this environment allows us to imagine life at a precise moment".

The ongoing excavation is taking place on the southern slopes of the Coelian Hill, one of Rome's seven hills, which in imperial times was home to luxury aristocratic residences and, further to the south, a series of military buildings, including a barracks recently found in Via Ipponio.

The stretch of metro from Amba Aradam to the Imperial Fora is scheduled to be unveiled in 2021.